Holographic data storage system

ABSTRACT

Apparatus is disclosed that comprises a holographic memory device in which a plurality of data packets are stored as diffractive patterns, a beam system adapted to transmit a reference beam to the memory device to read the packets sequentially, a microlens array, a solid state scanning system (e.g a microoptoelectromechanical device) and a photodetector array in which the microlens array is adapted to focus the output beam corresponding to each data packet on the same spatial area in the central part of a solid state scanning system and the solid state scanning system then routes it to a photodetector array. This allows the use of a fast solid state scanning system, which has a limited angular scanning range, without losing data at the edge of the matrix of points in which the data packet is recorded.

FIELD OF THE INVENTION

The present invention generally relates to photonics data memorydevices. In particular, the present invention relates to a microlensused in reading data memory devices.

BACKGROUND OF THE INVENTION

There is a strong interest in high-capacity data storage systems withfast data access due to an ever-increasing demand for data storage.Limitations in the storage density of conventional magnetic memorydevices have led to considerable research in the field of opticalmemories. Holographic memories have been proposed to supersede theoptical disc (compact disc read only memories, or CD-ROMs, and digitalvideo data, or DVDs) as a high-capacity digital storage medium. The highdensity and speed of holographic memory results from the use ofthree-dimensional recording and from the ability to simultaneously readout an entire page of data. The principal advantages of holographicmemory are a higher information density, a short random-access time, anda high information transmission rate.

In holographic recording, a light beam from a coherent monochromaticsource (e.g., a laser) is split into a reference beam and an objectbeam. The object beam is passed through a spatial light modulator (SLM)and then into a storage medium. The SLM forms a matrix of cells thatmodulate light intensity with grey levels. The SLM forms a matrix ofshutters that represents a page of binary or grey-level data. The objectbeam passes through the SLM, which acts to modulate the object beam withbinary information being displayed on the SLM. The modulated object beamis directed to one point, after an appropriate beam processing, where itintersects with the reference beam after being routed by an addressingmechanism. It is also contemplated that for multispectral holography,the multispectral hologram may be recorded with more than one wavelengthfrom different lasers or from the same multiline laser at the same time.In other words, the recording can be operating with several wavelengthsin the holographic multiplexing process.

An optical system consisting of lenses and mirrors is used to preciselydirect the optical beam encoded with the packet of data to theparticular addressed area of the storage medium. Optimum use of thecapacity of a thick storage medium is realized by spatial and angularmultiplexing that can be enhanced by adding frequency polarization,phase multiplexing, etc. In spatial multiplexing, a set of packets isstored in the storage medium and shaped into a plane as an array ofspatially separated and regularly arranged subholograms by varying thebeam direction in the X-axis and Y-axis of the plane. Each subhologramis formed at a point in the storage medium with the rectangularcoordinates representing the respective packet address as recorded inthe storage medium. In angular multiplexing, recording is carried out bykeeping the X- and Y-coordinates the same while changing the irradiationangle of the reference beam in the storage medium. By repeatedlyincrementing the irradiation angle, a plurality of packets ofinformation is recorded as a set of subholograms at the same X- andY-spatial location.

A volume (thick) hologram requires a thick storage medium, made up of amaterial sensitive to a spatial distribution of light energy produced byinterference of a coherent object light beam and a reference coherentlight beam. A hologram may be recorded in a medium as a variation ofabsorption or phase or both. The storage material responds to incidentlight patterns causing a change in its optical properties. In a volumehologram, a large number of packets of data can be superimposed, so thatevery packet of data can be reconstructed without distortion. A volume(thick) hologram may be regarded as a superposition of three-dimensionalgratings recorded in the depth of the recording photosensitive material,each satisfying the Bragg law (i.e., a volume phase grating). Thegrating planes in a volume hologram produce changes in refraction and/orabsorption.

While holographic storage systems have not yet replaced current compactdisc (CD) and digital video data (DVD) systems, many advances continueto be made which further increase the potential of storage capacity ofholographic memories. This includes the use of various multiplexingtechniques such as angle, wavelength, phase-code, fractal, peristrophic,and shift. However, methods for recording information in highlymultiplexed volume holographic elements, and for reading them out, havenot proved satisfactory in terms of throughput, crosstalk, and capacity.

Currently, to read data from a point in a holographic memory device, ascanning addressing method is used. This allows access to one packet ofdata recorded on an array of points. Using this method, geometricallimitation is induced, since the edge of the point matrix (i.e., theexternal points of the matrix) may not be sensed by a sensing device.This limitation comes from the fact that in a fast solid state scanningsystem that has a limited angular scanning range together with the sizeof the sensing the device, some of the data at the points at the edge ofthe matrix may be lost, since the sensing device may not be able tosense them. In other words, each point in the memory device/recordingplate defines a central part and a peripheric surrounding. Unlike thecentral part, where data packets can be sensed by a sensing device, thesensing device is unable to sense some of the information in the datapackets in the peripheric surrounding because of the optical aberrationand the limited field of the objective of the sensing device. A readingsystem is developed to be able to read the points at the edge of an evenbigger matrix.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a fuller understanding of the present invention,reference is now made to the appended drawings. These drawings shouldnot be construed as limiting the present invention, but are intended tobe exemplary only.

FIGS. 1A and 1B are schematic representations of an apparatus forrecording an interference pattern in accordance with one embodiment ofthe invention.

FIG. 2 is a schematic representation of an apparatus for reading theinterference pattern using a microlens in accordance with one embodimentof the invention.

FIG. 3 is a schematic representation of an array of microlenses used ina reading apparatus in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a reading system that comprises a solid statedynamic diffractive optical element device for reading information froma diffractive optics memory. The diffractive optics memory hasinformation stored therein, located at a plurality of points on thememory and at a plurality of angles at each one of the points so as toform a plurality of packets of information at each of the points. Thediffractive optics memory is arranged in the form of a matrix, oralternately, may be arranged in other forms, such as a tape or a disk.The matrix of the dynamic diffractive elements device is a routingdevice and is configured to shape and angularly direct a wavefront of acoherent light beam to the memory at one of the angles of one of thepoints to reconstruct one of the packets of information. In oneembodiment, the dynamic routing is based on the use of dynamic grating.The dynamic grating is a diffractive structure that is engineered tochange the diffractive effect by changing the dynamically in acontrolled way. The way the grating is produced controls the duration ofthe output diffracted beam. The present invention introduces the use ofa microlens arranged in a microlens matrix for reading holographicmemory. The microlens is positioned on the output beam path to focus theoutput beam to an addressing device. The microlens is located close to apoint of a matrix of the holographic memory to achieve the local storagecapacity while optimizing the focusing of all of the data packets on theaddressing device. The addressing device is used to address or routethese packets of data embedded in the output beam toward a sensingdevice through an imaging lens. By this means, all of the extendedrecording points can provide data packets that can be read by thesensing device, since these packets of data (images) are in the sensingfield of the sensing device (e.g., charge-coupled device (CCD) camera).

Further advantages and novel features of the present invention willbecome apparent to those skilled in the art from this disclosure,including the following detailed description, as well as by practice ofthe invention. While the invention is described below with reference toillustrative embodiments, this description is not intended to beconstrued in a limiting sense. Those of ordinary skill in the art havingaccess to the teachings herein will recognize additionalimplementations, modifications, and embodiments, as well as other fieldsof use, which are within the scope of the invention as disclosed andclaimed herein, and with respect to which the invention could be ofsignificant utility.

Storing/Recording Phase

FIG. 1A is a schematic representation of an apparatus for recording aninterference pattern in accordance with one embodiment of the invention.In a recording phase, a laser provides a laser beam (i.e., coherentlight beam) to the beam splitter system. The laser may be a YAG doubledlaser (i.e., a solid state laser) where a rod of YAG material emitslaser light in the infrared to the laser. The laser beam emanating fromlaser is split into a reference beam 102 and an object beam 103. Thereference laser beam 102 interferes coherently with the object beam 103to form the interference patterns or holograms 107, which are stored inthe recording medium due to the perturbation in the refractive index.Thus, each hologram is stored at a unique angle of the reference beam α.The separation between the various holograms stored within the samevolume relies on the coherent nature of the hologram in order to allowits retrieval in phase with the volume only for a defined angle value.In one embodiment, a nonlinear crystal (i.e., KDP) is used to double thefrequency of a laser. For instance, the YAG is naturally emitting in theinfrared by using a KDP in the YAG laser beam output. The KDP transformsthe infrared light from the YAG laser into a green light. In otherwords, the emitted frequency is effectively doubled. This process allowsthe laser to provide a green light out of an infrared laser light. Thisdoubled frequency is also coherent and the resulting wavelength fits thesensitivity of the recording material.

The memory device 101 has a plurality of cells to hold the recordedinformation. The memory device 101 is a holographic memory device thatcontains information stored during a phase of storing information. Thememory device 101 is typically a three-dimensional body made up of amaterial sensitive to a spatial distribution of light energy produced byinterference of the object beam 103 and the reference light beam 102. Ahologram (e.g., pattern 107) may be recorded in the medium 101 as avariation of absorption or phase or both. The storage material respondsto incident light pattern modulations, causing the change in its opticalproperties. In a volume (thick) hologram, a large number of packets ofdata can be superimposed, so that every packet of data can bereconstructed without distortion. The volume hologram may be regarded asa superposition of three-dimensional gratings recorded in the depth ofthe layer of the recording material, each satisfying the Bragg law(i.e., a volume phase grating). The grating structures in a volumehologram produce change in refraction and/or absorption. The memorydevice 101 may be arranged in the form of a flat layer, herein referredto as a matrix (see FIG. 1B). Each of a plurality of points on thematrix is defined by its rectilinear coordinates (X,Y). An image-formingsystem (not shown) reduces the object beam 103 to the sub-hologram 108 ahaving a minimum size at one of the X,Y point of the matrix. A point inphysical space, defined by its rectilinear coordinates, contains aplurality of packets 108 b.

In one embodiment, the memory device 101 is constructed of organicmaterial, such as a polypeptide material, and made in accordance withthe techniques described in the co-pending patent application entitled“Photonics Data Storage System Using a Polypeptide Material and Methodfor Making Same,” Serial No. PCT/FR01/02386, which is hereinincorporated by reference.

A display may be any device for displaying data packets in a system,such as spatial light modulators (SLMs) or liquid crystal light valves(LCLVs). The plurality of bits represented on the display screen of thedisplay is presented as a two-dimensional pattern of transparent andopaque pixels (i.e., data packet). The data packet displayed is derivedfrom any source such as a computer program, the Internet, and so forth.In an Internet storage application, the packets displayed may beformatted similarly to the packets of the Internet.

The object beam 103 after passing through the display, acts to modulatethe object beam 103 with the binary information. The object beam 103 isthen directed to a defined point on the recording medium 101 where itintersects with the reference beam 102 to create a plurality ofinterference patterns loaded with data packets. A lens (not shown) maybe used to converge the modulated object beam 103 and to focus the beamto the recording medium 101. In other words, the modulated beam 103becomes reduced by means of a suitable lens so that the point ofconvergence of the modulated object beam lies slightly beyond therecording medium 101. The reference beam 102 and the object beam arepositioned at different angles by the angular multiplexing method sothat a plurality of data packets is recorded at one point of therecording medium 101.

As stated above, the recording system, as shown in FIG. 1A, includes thesingle reference beam 102, the object beam 103, and the recording medium101. The reference beam 102 and the object beam 103 intersect to formpatterns to be recorded on the recording medium 101 at an X,Y location.The reference beam 102 is angularly multiplexed so that different datacan be recorded on one point (e.g., point 108 a) of the recording medium101. The reference beam 102 is also spatially multiplexed so that datacan be recorded on different points of the recording medium 101 (seeFIG. 2). This is the spatial multiplexing that is carried out bysequentially changing the rectilinear coordinates. Angular multiplexingis achieved by varying the angle α of the reference beam 102 withrespect to the surface plane of the storage medium 106. The separatepacket of information 107 is recorded in the storage medium 101 as adiffraction pattern (e.g., a sub-hologram) for each selected angle α andspatial location. Spatial multiplexing is achieved by shifting thereference beam 102 with respect to the surface of the storage medium 101so that a point (e.g., point 108 a) shifts to another spatial location,for example, point 108 a′, on the surface of the storage medium 101. Thespatial multiplexing is carried out by sequentially changing therectilinear coordinates. Angular multiplexing is carried out bysequentially changing the angle of the reference beam 102 by means ofmirrors (not shown). A data packet is reconstructed by shining thereference beam 102 at the same angle and spatial location at which thedata packet was recorded. The portion of the reference beam 102diffracted by the storage medium material forms the reconstruction,which is typically detected by a detector array. The storage medium 101may be mechanically shifted in order to store data packets at differentpoints by its coordinates (X,Y).

The storage medium 101 is arranged in a matrix. Each of a plurality ofpoints on the matrix is defined by its rectilinear coordinates signalsinvolved in recording a diffraction pattern (i.e., a hologram) in astorage medium using angular and spatial multiplexing. Variousdiffractive recording processes have been developed in the art, andfurther details can be found in the book Holographic Data Storage by H.J. Coufal, D. Psaltis, and G. T. Sincerbox (Springer 2000). It iscontemplated that a storage diffractive pattern, in some cases, can alsobe implemented by using techniques other than the interference of areference and object beam, such as using an e-beam and amicrolithography process for etching materials to generate diffractivestructures.

Reading Phase

FIG. 2 shows a schematic representation of a reading and addressingsystem according to one embodiment of the present invention. The readingand addressing system 200 includes the memory device 201, refractive ordiffractive microlenses array 210, an addressing device (e.g.,microoptoelectronomechanical system, or MEOMS) 204, an imaging lens 203,a sensing device (e.g., CCD camera) 202 and a laser 207. The sensingdevice 204 may be a solid-state chip produced by microlithography andincludes micromechanical electronics and photonics.

The microlenses array 210 includes a plurality of microlenses 206 ₁ to206 _(N) that are positioned or located in front of each correspondingpoint in the point matrix on the recording medium 201. The correspondingrecorded points are in the paths between the memory device 201 and theaddressing device 204 (i.e., each point is dedicated to itscorresponding microlens arranged in the microlens array 210). Eachmicrolens from the microlens array 210 is calculated and realized tofocus its corresponding output beams carrying the output pages 205 ₁ to205 _(N). The output beams (i.e., output pages) are focused on the samespatial area on the addressing device 204 as shown in FIG. 2. Thepositioning of the microlenses 206 ₁ to 206 _(N) is calculated through acomputer-aided design/computer-aided manufacturing (CAD/CAM). Themicrolenses 206 ₁ to 206 _(N) provide a wider range of field sensing andaberrations without increasing the angle of the sensing device 202. Themicrolenses 206 ₁ to 206 _(N) are used to focus the output beams to theaddressing device 204. The microlenses at the output pages provide abetter reading of data located at the edge of the information points.This extends the storage surface, and therefore increases the storagecapacity. The increase of capacity in the storage device (i.e., memorydevice 201) is due to the fact that there is more surface area availablefor storage by using the edge area for storing information.

Referring to FIG. 3, there is shown a schematic representation of anarray of “i” microlenses and their related focal lengths according toone embodiment of the invention. The calculation of the focal lensesdepends on the localization of these lenses in the microlens array 210.The focal length f_(i) (i.e., the distance between the microlens i^(th)to the point on the addressing device 204), is calculated according tothe following formula:$f_{i} = \frac{h_{i}}{\sin\left( {{atan}\left( {h_{i}/d} \right)} \right.}$

where h_(i) is the Y-axis (i.e., vertical) distance between the centerpoint of the i^(th) lens and the point on the addressing device 204; and

d is the X-axis (i.e., horizontal) distance between the cent FIG.erpoint of the i^(th) lens and the point on the addressing device 204.

α is the angle in which the i^(th) lens is positioned with respect tothe X-Y axis. The determining of the angle α for every lens reference isthe “i” number (i.e., the order of the microlens in the matrix ofmicrolenses). The angle α is determined by using optical CAD/CAMsoftware. In other words, a is the tilt value between the i^(th) lensplane and vertical axis is calculated using the CAD/CAM. The CAD/CAMsoftware provides calculation in such a way that all the microlenses inthe array focus on the same points located in the central part of theaddressing system 204 (e.g., MEOMS). In one embodiment, the diameter ofthe microlens is 1 mm and the lens centers are spaced by 1 mm. Referringback to FIG. 2 where the microlenses 206 ₁ to 206 _(N) focus on onepoint of the addressing device 204 (i.e., the focusing point is commonto all the lenses in the microlens array). This point is located on theaddressing device 204 for routing the beam to the sensing device 202.Each lens has a different focus depending on its location on the arrayplane. The calculation of each lens depends on its correspondingrecording point on the memory device 201. The value of the focusingpoint changes and is then calculated through an optical CAD/CAM. Thepositions of the microlenses are calculated to address every packet ofthe memory device 201. The diameter of each lens matches or correspondsto the size of its recording point. The size of the lenses correspondsto the size of the beam and the divergence of the output beam. The sizeof lenses also depends on the wavelength used for reading. Theaddressing device 204 allows the synchronized reading of the entireextended matrix at high speed, operating packet by packet and using thesensing device 202. Since there is no need to electronically correcteventual disalignment due to errors in electro opto mechanicaladjustment, the reading is fast. Furthermore, with appropriateprogramming the addressing device 204 compensates the geometrical noise,and the sensing device 202 can sense all the data in the targeted area.

The addressing device 204 may be composed of electronics, mechanics,optics or other elements. In one embodiment, the addressing device 204is a MEOMS and is engineered and programmed to address the beam movingfrom one point to the sensing device 202. The MEOMS 204 is theintegration and combination of optics with electronics and mechanics.Various types of MEOMS have been developed in the art and furtherdetails can be found in the book entitled Digital Diffractive Optics: AnIntroduction to Planar Diffractive Optics and Related Technology, by B.Kress and P. Meyrueis (Wiley and Sons, 2000). In one embodiment, theMEOMS 204 is designed to allow a synchronized reading of the entireextended matrix in the memory device 201 at a high speed. The MEOMS 204addresses the matrix of points on the memory 201 in which data isrecorded by spatial and angular multiplexing. Since only one sensingdevice 202 is used, the reading is sequential, i.e., packet by packet.All the outputs of the microlenses are focused on the addressing device204. The addressing device 204 then routes the beam to the sensingdevice 202. The routing depends on the voltage applied to the addressingdevice 204 to obtain the right deflection. The output beam from eachmicrolens depends on its location in the microlens array. A specificvoltage is calculated, optimized and stored into a memory (e.g.,computer memory) for each location of the microlens. The voltage appliedto the frame of the appropriate sequence depends on the operationalmicrolens. This sequence is synchronized with the sensing device 202.For simple programming of the addressing device 204, all beams arelocated in one plane.

The imaging lens 203 focuses the beam from the point on the addressingdevice 204 to the sensing device 202. To optically optimize, the sensingdevice 202 is located on the same focal plane of the imaging lens 203.This reduces noise, and therefore provides quality data. One way inwhich the optical optimization occurs is in the utilization of thefunction transfer modulation (FTM) method, which is used for opticallyoptimizing the sensed beam by the sensing device 202. Another way isthrough the use of an optical CAD/CAM. The optical CAD/CAM defines thecharacteristics of the lens (e.g., focus, diameter of the lens, materialfocus, etc). The geometrical positioning of the lens in the systemdepends on the size of the output image. The CAD/CAM also provides thepositioning and the size of the addressing device 204 to be used in thereading system. This provides accuracy in which data is specified with atolerance level that fits the recording tolerance of the material usedin the recording plate 201.

The sensing device 202 may be any sensor that can sense the images fromthe output of the addressing system 203. The sensing device 202 may bemade of CCD or CMOS (complementary metal-oxide-semiconductor) activepixel sensors (APS). In one embodiment, the sensing device 202 is acharge-coupled diode. The imaging lens 203 focuses the light energy fromthe MEOMS 204 onto the sensing device 202 to read a given packet ofmemory 201.

The reference beam, split from a beam of the laser (i.e., read beam) bya beam splitter, emanates from the low-power laser (not shown).Typically, the reference beam is less than 5 mW. The laser may be ahelium-neon or semiconductor-type laser. The reference beam may bemodulated by means of one or more transformation activators (not shown)lying in the optical path of the beam.

A plurality of sequential beams, which contain a plurality of outputpages carrying data/information in the memory device, are created by areference laser beam. Corresponding to each of the beams is a microlensin the array 210, which focuses one of the array of beams 205 ₁ to 205_(N) onto the addressing device 204 (i.e., one lens per point). In oneembodiment, the addressing device 204 is a MEOMS that includes a smallmirror (e.g., 2×2 millimeter mirror). Thus, for a matrix with 10 columnsand 10 rows, for example, there would be 100 microlenses. The MEOMS 204focuses the beams through an imaging lens 203 onto a sensing device(e.g., CCD camera) 202. The reading system 200 represents a solid statebeam routing system that performs output beam routing without mechanicalsensor adjustment.

Retrieving the recorded/stored information from the recording medium 201requires the use of the reference beam (i.e., read beam) whosecharacteristics correspond to those employed for writing or for storage.The reference beam induces diffraction due to perturbation in therefractive index corresponding to the characteristics of the beam,thereby creating a data loaded modulated beam.

The reference beam is positioned in order to access a plurality of datapackets contained at a defined point (X,Y) on the matrix in therecording medium 201. The reading procedure is similar in the addressingangle values to the writing or recording procedure. However, the readingprocedure may be carried out with a greater degree of tolerance than therecording procedure. It is possible to use a very compact laser sourceof a solid-state type for the reading process because the laser powernecessary for reading is much lower than the one for recording.

The plurality of data packets in the recording medium 201 isreconstructed simultaneously by shining the reference beam (i.e., readbeam) 208 at the same location in which the data packets were recorded.The reference beam 208 diffracted by the recording medium 201 forms thereconstruction of stored data packet, which is detected by the pluralityof arrays of image sensors 202. The reference beam 208 is configured toaddress the plurality of packets at different locations in the recordingmedium 201. The plurality of lenses 206 ₁ to 206 _(N) is positioned atdifferent angles to focus the reference beam 208 onto the addressingdevice 204. The addressing device 204 then addresses the beam to thesensing device 202. The reference beam 208 is shaped and directed by thelaser 207 onto the recording medium 201 and from there focused byimaging lenses 206 ₁ to 206 _(N) onto the addressing device 204, andthen to the image sensor 202 (e.g., CCD camera), by the imaging lens203, which has a number of pixels adapted to the desired resolution. Thedigital output of the image sensor 202 is further processed by acomputer (not shown).

The present invention is not to be limited in scope by the specificembodiments described herein. Indeed, this application is intended tocover any modifications of the present invention, in addition to thosedescribed herein, and the present invention is not confined to thedetails which have been set forth. Thus, the scope of the inventionshould be determined by the appended claims and their legal equivalents,rather than by the examples given.

1. An apparatus comprising: a recording medium for diffractivelyrecording information designated to a cell; a laser for transmitting areference beam to the recording medium; and an object beam device fortransmitting a sequence of object beams to the recording medium atdifferent angles, the object beams intersecting the reference beam atdifference angles within the recording medium to form a plurality ofpatterns.
 2. The apparatus according to claim 1 further comprising adisplay loaded sequentially by information packets for displaying theinformation to be recorded, the object beams being modulated byreflection off or transmission through the displays.
 3. The apparatusaccording to claim 2 further comprising a lens for focusing thesequentially modulated beam to a point on the recording medium.
 4. Theapparatus according to claim 1 wherein the recording medium is apolypeptide diffractive holographic memory device.
 5. The apparatusaccording to claim 2 wherein the display is a spatial light modulator(SLM).
 6. The apparatus according to claim 1 wherein the cell includes aplurality of interference patterns.
 7. The apparatus according to claim1 wherein the recording medium is made of polypeptide material.
 8. Anapparatus comprising: a recording medium for recording informationdesignated to a cell; a laser for transmitting a reference beam to therecording medium; and an object beam device for transmitting objectbeams sequentially to the recording medium at different angles, theobject beams simultaneously intersecting the reference beam within therecording medium to form a plurality of patterns.
 9. An apparatuscomprising: a recording medium for recording information designated to acell; a laser for transmitting a reference beam to the recording medium;an object beam device for transmitting object beams sequentially to therecording medium at different angles, the object beams intersecting thereference beam within the recording medium to form a plurality ofpatterns; and a display for sequentially displaying the information tobe recorded, the object beams being modulated by reflection off ortransmission through the display.
 10. An apparatus comprising: arecording medium for recording information designated to a cell; a beamsplitter system for transmitting a reference beam to the recordingmedium; an object beam device for simultaneously transmitting objectbeams sequentially to the recording medium at different angles, theobject beams intersecting the reference beam within the recording mediumto form a plurality of patterns; and a display for displaying theinformation to be recorded, the object beams being modulated byreflection off or transmission through the display.
 11. A methodcomprising: transmitting a reference beam to a recording medium;sequentially positioning an object beam at different angles;transmitting the object beam to the medium; and intersecting thereference beam and the object beam within a cell in the recording mediumto form a plurality of patterns.
 12. The method according to claim 11further comprising: displaying information to be recorded on a display;and modulating the object beam by reflecting off or transmitting theinformation through the display.
 13. The method according to claim 12further comprising converging the modulated object beams.
 14. The methodaccording to claim 13 wherein the recording medium is a polypeptidelayer.
 15. The method according to claim 12 wherein the display is aspatial light modulator.
 16. The method according to claim 11 whereinthe object beams include the plurality of interference patterns.
 17. Themethod according to claim 11 wherein the recording medium is made ofpolypeptide material.
 18. A method comprising: transmitting a referencebeam to a recording medium; sequentially arranging object beams atdifferent angles; simultaneously transmitting the object beams to themedium; and intersecting the reference beam and the object beams withina cell in the recording medium to form a plurality of patterns.
 19. Amethod comprising: transmitting a reference beam to a recording medium;sequentially arranging object beams at different angles off a referencebeam; transmitting the object beams to the medium; intersecting thereference beam and the object beams within a cell in the recordingmedium to form a plurality of patterns; and storing information to beread on a sequential display.
 20. The method according to claim 19further comprising modulating the object beams by reflecting off ortransmitting the information through the display.
 21. The methodaccording to claim 20 further comprising converging the modulated objectbeams.
 22. An apparatus comprising: a memory device including a cell forcontaining recorded information; a beam splitter system for transmittinga reference beam to the memory device to read the recorded information;and an object beam device for transmitting object beams sequentially tothe recording medium at different angles, the object beams intersectingthe reference beam within the recording medium to form a plurality ofpatterns.
 23. The apparatus of claim 22 wherein the object beam deviceis a diffractive optic element.
 24. The apparatus of claim 22 whereinthe object beam device is a cascade of beam splitters.
 25. An apparatuscomprising: a memory device having a plurality of patterns; a beamsystem for transmitting a reference beam to the memory device to readthe plurality of patterns sequentially; a plurality of lenses forforming images of the patterns; and means for converting the images intoelectrical signals.
 26. The apparatus according to claim 23 whereinmeans of converging is a charge-coupled device (CCD).
 27. The apparatusaccording to claim 24 further comprising a computer for processing andanalyzing the electrical signals.